The problem of land erosion adjacent to waterways such as rivers, streams, lakes and oceans, has traditionally been combatted by the use of wood, steel or cement construction. Efforts to limit erosion along these waterways have also included the use of a series of bulkhead strips made from a plastic material.
One such system is described in U.S. Pat. Nos. 4,674,921 and 4,690,588 to Berger and marketed by C-Loc.RTM. Retention Systems, Inc. of Utica, Mich. incorporated herein in their entirety by reference. This system includes a series of interlocking corrugated bulkhead strips, which are interconnected to form a barrier of heavy duty, exterior grade polyvinyl chloride (PVC). Each strip includes a male and female shaped edge and is lifted and slid into interengagement within an adjacent strip and manually driven into the ground. To assist in reinforcing and shoring up of the assembled seawall, an anchoring system is embedded in the ground.
The anchoring system includes a plurality of laterally spaced elongated, corrugated anchor strips, preferably constructed of PVC, which are embedded in the ground at an acute angle to the seawall. The spaced anchor strips, referred to as dead man strips, are inclined upwardly and outwardly with respect to the seawall and are connected thereto by a series of horizontally disposed and laterally spaced tie rods or tie backs. The corrugated anchor strips include transversely extending walers. Each waler is hollow, preferably rectangular in cross section, flexible, and made of a plastic material, such as PVC. The tie rods have threaded ends which extend through the corresponding anchor strip and the opposed adjacent bulkhead strip. Walers are mounted on opposite ends of the rod and secured thereto by flat washers and nuts.
The walers are resilient for transferring and distributing the forces applied to the seawall from an individual corrugated strip or plurality thereof, back to the corresponding opposed anchor strips. If the distance the seawall extends above the water level is considerable, it is contemplated that a second set of laterally spaced tie rods will be employed, vertically aligned with corresponding tie rods for reinforcement of the seawall along its length.
Another system using a plastic panel erosion barrier wall is disclosed in U.S. Pat. No. 5,145,287 to Hooper et al and distributed under the name ShoreGuard.TM. Vinyl Seawall by Materials International, Inc. of Atlanta, Ga. also incorporated herein in its entirety by reference. In this patent a corrugated plastic panel strip is described with opposed male and female interlocking edges provided for mating association with adjacent panel strips.
To assist in securing the position of the formed wall, a concrete anchor is provided a distance back from the wall and embedded below the ground level. A tie rod holds the wall in place by being connected to a reinforcing rod embedded in the cement cap of the wall and extending back to a reinforcing rod similarly embedded in the concrete anchor. The tie rod is connected between the two reinforcing rods in the concrete wall cap and the concrete anchor by bending the ends of the tie rod about the reinforcing rods.
In a seawall having a sufficient height, an additional lower level of tie rods are used to interconnect the strips of the seawall with a concrete anchor which is also connected to the concrete cap of the seawall by a second set of tie rods. The tie rods connected below the level of the tie rods connected to the cap impart a greater strength to a deep wall. The lower set of tie rods extend through the panel strip of the seawall and through a waler positioned on the exterior surface of the seawall, while the tie rods are provided at spaced distances along the length of the wall depending upon the strength to be imparted and required to hold the waler in place.